For indicating a molecular structural diagram of a compound on a display or outputting it through a printer, it was common practice heretofore to use the molecular structural diagram hand-written with a mouse or the like by a man. For molecular structural diagrams simple in structure, it was also possible to automatically produce the molecular structural diagrams by arithmetic based on bond information of each atom. The minimization method was invented as a producing technique thereof. The minimization method is suitable for producing molecular structural diagrams of compounds of the monocyclic structure including the relatively small number of ring-constituting members.
The minimization method will be explained. For example, in the case of a compound being a single six-membered ring, the molecular structural diagram thereof is of a hexagon. Letting the sides of this hexagon be r1 to r6 and .theta.1 to .theta.6 be the vertices thereof, the arithmetic is carried out so as to minimize ##EQU1## thereby obtaining the values (r1 to r6 and .theta.1 to .theta.6). Here, r.sub.0, .theta..sub.0 are standard values, for example, r.sub.0 =1.5 and .theta..sub.0 =120.degree.. Further, k.sub.r, k.sub..theta. each are weights, which are positive constants.
This arithmetic will result in obtaining r1=r2= . . . =r6=r.sub.0 and .theta.1=.theta.2= . . . =.theta.6=.theta..sub.0. This means that the minimization method produces a generally regular hexagon as a molecular structural diagram of six-membered ring.
Neither of the conventional methods as described above, however, was suitable for producing complex molecular structural diagrams of single rings with many ring-constituting members and fused rings.
Namely, when complex molecular structural diagrams were produced by hand-writing, configurations thereof often became distorted, which was a problem. When the complex molecular structural diagrams were produced by the minimization method, a lot of processing time was necessitated, which was a problem.
It is thus an object of the present invention to provide a producing apparatus, producing method and storage medium for production, of molecular structural diagram, that can automatically and quickly produce a molecular structural diagram easy to grasp the structure visually, excellent in an aesthetic sense, and of common use.